A 7-day continuous intravenous infusion of cytosine arabinoside plus a 3-day schedule of intermittent daily doses of adriamycin has been shown to be as effective in the induction of remission in adults with acute nonlymphocytic leukemia as the combination of cytosine arabinoside with daunorubicin. A complete remission rate of 65% has been obtained with either combination. However, the adriamycin combination has been shown to be more toxic and to require more careful dosage adjustment and monitoring of blood levels. At present it is too early to discern whether the addition of either neuraminidase-treated allogeneic myeloblasts or splenectomy to chemotherapy during remission maintenance treatment enhances the duration of remission or survival of patients. Reverse transcriptase has been identified in the bone marrow cells of leukemia patients prior to treatment and in morphologically normal peripheral cells during complete remission. This may suggest that morphologically and functionally normal granulocytes in the peripheral blood of leukemia patients in complete remission may actually be derived from leukemic cells.